The Most Practical Technology in Coal Preparation Plant

Ten Common Faults of Screening Machine and Their solutions

• Fault 1: screen does not vibrate

Phenomenon: the motor only hums and does not start

Treatment: check the motor, check the vibration exciter, and deal with it.

• Fault 2: exciter overheating

Phenomenon: the temperature of exciter exceeds the specified temperature

Treatment: check the oil, oil quality and oil quantity, check the bearings and gears, and replace the exciter if there is any problem.

• Fault 3: high vibration 

Phenomenon: the sound is loud in steel structure support

Treatment: check whether the fixed steel parts interfere with the screen body, whether there is material accumulation on the chute, whether the spring is damaged, and deal with it accordingly.

• Fault 4: abnormal sound

Phenomenon: abnormal sound during operation 

Treatment: stop the machine and check whether the spring is damaged, whether there are loose parts, whether the exciter cover is damaged, whether the bearing is damaged, whether the exciter gear is damaged, and make corresponding treatment.

• Fault 5: too much material under screen

Phenomenon: too much material under screen

Treatment: check the screen plate for wear or breakage, and replace it.

• Fault 6: the material on the screen is smaller than the material through the screen

Phenomenon: the material on the screen is smaller than the material through the screen

Treatment: insufficient water spray or clogged sieve plate hole, increase water spray volume or increase the number of spray nozzles or adjust the spray angle, clean or replace sieve plate.

• Fault 7: uneven incoming materials

 Phenomenon: the thickness of left, middle and right of screen material is not equal

 Treatment: the foreign matters in the feeding part are blocked, and stop for cleaning.

• Fault 8: rubber connecting plate damaged

Phenomenon: the rubber disk has cracks or noise here

Treatment: check whether the connecting shaft is in a straight line, readjust and replace the connecting disk.

• Fault 9: rail seat beam broken

 Phenomenon: abnormal sound under screen surface

 Treatment: check the rail seat beam. If the broken rail seat beam does not contact the girder, repair welding can be conducted in case of emergency treatment; replace the rail seat beam.

• Fault 10: irregular motion of screen machine

 Phenomenon: abnormal screen vibration

 Treatment: check whether the spring is damaged, whether the screen plate is loose, whether the screen surface is blocked by material accumulation, whether the material flows to one side of the screen machine, whether the beam screen side is broken, and make corresponding treatment.

Five Common Faults of Crusher and Their solutions

• Fault 1: Super granularity

Phenomenon: lots of coarse coal

Treatment: check whether the crusher tooth plate is broken, whether the tooth of the tooth plate is broken, whether the tooth plate is worn, and replace the tooth plate.

• Fault 2: can not be broken

Phenomenon: the motor rotates, the reducer rotates, and the coal overflows from the crusher

Solution: cut off the power and check the coupling from reducer to crusher.

• Fault 3: shutdown in operation

Phenomenon: locked rotor alarm

Treatment: check whether there is hard blockage in the crusher after power failure, and check whether the locked rotor switch is normal, and deal with it.

• Fault 4: main bearing temperature too high

 Phenomenon: the temperature of main bearing exceeds the specified temperature

 Treatment: check the amount of grease and pollution, check whether the bearing is damaged and deal with it.

• Fault 5: reduced processing power

Phenomenon: the motor rotates, the reducer rotates, and a small amount of coal overflows from the crusher

Treatment: check whether the hydraulic coupling leaks is damaged, and then handle it.

Four Common Faults of Coal Feeder and Their Solutions

• Fault 1: feeder does not discharge

 Treatment: check the running direction of the two motors and whether the soft connection is broken.

• Fault 2: uneven cutting

 Treatment: check whether there is coal deposit on the bottom plate.

• Fault 3: motor overload

 Treatment: check whether there is much coal around the bottom plate and dustpan, resulting in no gap between the dustpan and the discharge chute.

• Fault 4: backward coal overflow

 Treatment: due to the small slope of dustpan, large moisture content of coal or large feeding amount, adjust the slope and feeding ram.

Nine Common Faults of Belt Conveyor and Their Solutions

• Fault 1: the reducer does not rotate 

Phenomenon: the belt motor and hydraulic coupling are running, the reducer is not running, the hydraulic coupling fusible plug is normal, the oil level is normal, the backstop is free of temperature and peculiar smell. 

Treatment: from easy to difficult troubleshooting, first check the reducer, then check and replace the backstop, and then check the hydraulic coupling.

• Fault 2: the belt conveyor fails to start

Phenomenon: the motor does not run.

Treatment: check and remove the protection faults (stall alarm, dredge the chute, reset the pull rope switch, reset the emergency stop button), and check the motor.

• Fault 3: belt deviation

Phenomenon: when the belt conveyor is in normal operation, the belt starts to deviate along a certain point.

Treatment: check whether there is slime or sundries on the roller and idler, check whether there is too much coal on the lower belt, and clean it.

Phenomenon: the whole conveyor belt runs to one side.

Treatment: drum is not parallel, mostly due to tail drum deflection or tail drum slime.

Phenomenon: the belt runs to one side, and the deviation is at the joint of the belt.

Treatment: if the joint is not correct, it shall be remade according to the standard.

Phenomenon: the direction of belt deviation is uncertain, left and right.

Treatment: insufficient tension, adjust the belt tension.

Phenomenon: the belt does not deviate under no load, and it deviates under load.

Treatment: adjust the coal dropping point or increase the supporting roller if the material falling is partial or the supporting roller under the loading point is damaged or missing.

Phenomenon: the middle part of the belt conveyor deviates.

Treatment: move the deviation idler according to the situation.

• Fault 4: belt damage

Phenomenon: the belt stops running and is damaged

Treatment: the belt is seriously deviated, and the belt joint is torn on the frame or roller bearing seat; check whether the equipment parts fall off, the iron is stuck in the blanking chute and the belt room; whether there is large coal and gangue; whether there is chute liner fall off; the transmission roller stalls; the roller and the idler are damaged and scratched; the idler is stuck and inflexible; there is iron wire and other sundries stuck between the cleaner and the belt 。

• Fault 5: tape slipping

Phenomenon: the resistance of the tape is too large.

Treatment: loading goods should not be too much and there should not be a large number of idlers that do not rotate.

Phenomenon: the tape tension is small.

Treatment: adjust the tension device, adjust the deformation and elongation of the new belt after a period of operation.

Phenomenon: the friction coefficient between the belt and the driving drum decreases.

Treatment: avoid the contact surface of the belt driving roller from entering mud water or washing water when cleaning.

• Fault 6: Spray

 Phenomenon: spray material at transfer point.

 Treatment: spray materials in chute and guide chute, check whether the conveyor is seriously overloaded and whether the rubber apron of guide chute is damaged.

Phenomenon: sprinkling in case of deviation.

Treatment: adjust the deviation of the tape.

Phenomenon: when the conveyor is started, the concave section will spring up and sprinkle materials.

Treatment: the concave part of the conveyor is provided with a belt pulley to prevent the belt from springing up.

• Fault 7: abnormal noise

Phenomenon: noise caused by serious eccentricity of idler.

Treatment: replace the idler.

Phenomenon: noise when two shafts of coupling are not concentric.

Treatment: adjust the position of motor and reducer.

Phenomenon: abnormal noise of steering drum and driving drum

Treatment: check the bearing at the bearing seat.

• Fault 8: short belt life

Phenomenon: the service life of conveyor belt is short.

Treatment: check whether the tape has been stored for a long time and cracks. Check the tightness of the cleaner to ensure that there is no material on the return tape.

• Fault 9: broken belt

Phenomenon: the belt breaks during operation.

Treatment: check whether the belt is overloaded, pull the empty belt when the machine is stopped, avoid heavy load starting, replace the idler without rotation in time, clean up the sundries and reduce the running resistance of the belt.

Phenomenon: fracture from joint. 

Treatment: if the tensile strength of the belt joint is not enough, the belt joint shall be checked frequently and replaced regularly, and the damaged joint shall be replaced in time.

（To be continued...）

Contact HOT Mining with your coal washing plant proposal!

Miss. Lynette         Email : lynette@miningmes.com            Tel/WA:+86 19113498960

Mr.Tari                 Email : tari.wang@hot-mining.com      Tel/WA:+86 15927439651